Two infections, forty-seven years apart

Correct answer: C. Antibodies raised against streptococcal antigens cross-react with cardiac and joint tissue

• A. Herpes simplex virus causes primary herpetic gingivostomatitis and recurrent herpes labialis. It has no role in the pathogenesis of rheumatic fever, which is a bacterial sequel.
• B. The organism is STREPTOCOCCUS PYOGENES. Staphylococcus aureus causes a different set of diseases and is not associated with rheumatic fever.
• C. CORRECT. Acute rheumatic fever is a delayed AUTOIMMUNE sequel to pharyngeal infection with GROUP A BETA-HAEMOLYTIC STREPTOCOCCUS. The mechanism is MOLECULAR MIMICRY: antibodies raised against streptococcal M protein cross-react with structurally similar antigens in the patient's own tissues — the endocardium, myocardium and pericardium, and above all the heart VALVES, along with joints, skin and brain. That is why the manifestations are a pancarditis with migratory polyarthritis, chorea, erythema marginatum and subcutaneous nodules, the Jones criteria. The valve damage is what persists.
• D. Asthma has no relationship to rheumatic fever.

Note: ⚠️ The dental consequence, and the error this history invites: a history of rheumatic fever ALONE — and even rheumatic heart disease with established valve damage — does NOT require antibiotic prophylaxis under the 2021 AHA guidance. Rheumatic valve disease was removed from the list in 2007. What DOES require prophylaxis is a PROSTHETIC VALVE, which many of these patients eventually receive, or a previous episode of infective endocarditis. Ask what happened AFTER the rheumatic fever, not merely whether it occurred.

Correct answer: A. Urgent referral for biopsy of the tonsillar lesion

• A. CORRECT. A UNILATERAL, persistent, ulcerated tonsillar lesion that has not resolved with antibiotics, accompanied by a firm ipsilateral cervical node, must be treated as OROPHARYNGEAL CARCINOMA until proven otherwise, and only biopsy settles it. In a 23-year-old non-smoker the aetiology to think of is HPV, particularly TYPE 16 — HPV-positive oropharyngeal cancer characteristically affects younger patients who neither smoke nor drink heavily, arises in the TONSIL and BASE OF TONGUE, and presents with a small primary lesion and a disproportionately prominent, often cystic, neck node. Because the tonsil sits at the boundary of dental and ENT territory, the correct route is urgent specialist referral rather than an office biopsy.
• B. Watching a persistent ulcerated lesion with an ipsilateral neck node for six months is indefensible. The working rule is that any oral or oropharyngeal ulcer persisting beyond two to three weeks without an obvious cause requires biopsy.
• C. Tonsillectomy as a therapeutic step before any diagnosis exists is the wrong order. A diagnostic tonsillectomy is sometimes how the specimen is ultimately obtained, but that is a decision for the surgeon after assessment.
• D. The lesion has ALREADY failed to respond to a full course of antibiotics, and that failure is precisely the finding that raises concern. Repeating them changes nothing except the delay before diagnosis.

Note: HPV-positive oropharyngeal carcinoma carries a considerably BETTER prognosis than HPV-negative disease and is staged separately for that reason — but the improved prognosis depends entirely on it being diagnosed. Youth and the absence of tobacco and alcohol history are exactly what makes clinicians dismiss these lesions, and that is the trap the case is built around.